Valve for rock drills



smans Feb. 23, 1932. w. A. SMITH, JR

v'ALvE FOR ROCK DRILLS Filed Dec. 8, i928 INVENTOR. Mfzlamfi'mida HJJA TTORNEK Patented Feb. 23, 1932 TBS PATENTOE F CE A. srrr'rn, 33., or: rHILLIrsBURe ivEw JEnsnY, assmuomo INGERsoLL- 341v]; COMPANY, or JERSEY" CITY, NEW anaemia conroaarronor ew musty VALVE Foa noon paints Application filed'neceniber 8,1928, Serial No. 324,725.

This invention relates to rock drills, but more particularly toa valve for eifectlng the distribution of pressure fluid to the cylinder of therock drill of the hammer type.

- The objects of the invention are to insure,

a steady andpositive action of the valve, and

to provide a substantially direct path from the source of pressure fluid supply to the ends of the cylinder.

in-part pointed outhereinafter. v y [In the drawings illustrating the 1nvention and in which sir'nilar referencecharacters refer to similar parts, v I

Figure 1' is a sectional elevation of-so serve to illus-v drill. having. in this instance a freeexhaustport B for conveying fluid from apiston chamber G in the cylinder. A reoiprocatory hammer piston D is dIlSPOSBdrID thepiston chamberG and carries a fluted extension E which extends in a forwardly direction to deliver: blowsof impact to a worki'ng'implement (not shown) and is guided by a bore F: of a front cylinder Washer G which serves as a closure for the front end of the piston chains berC. In the rearward end'of the cylinder A is an enlarged bore H for the reception of a valve chest designatedgenerallyby J. The valve chest J comprises a pair ofplates K and L. The plate L occupies the extreme innermost position in thebore H and acts as a closure for the rearward end of the piston chamber C. The plate J is seated on the plate L and C in turn acts asJa seat for: a rotation1ratchet O disposed in the rearward end Of'thQ bOr-BuH-v 1 1 The rotation ratchet O-may be-zof a well known typeand is provided with'the usual teethrP to serve as abutments for sprin pressed pawls F carried by the head R of a rifle bar S. The rifle bar S extends through the plates K and L andfissuitably fluted for i Other objects will be. in part obviouslandslidable engagement with the piston'D as is the usualpractice; V v 4 v f Disposed at the rearward endof the cylinder Aland. seated on the rotation ratchet O is a backheadTwhich may be secured to the'cylinder in anysuitable manner as for in stancebyzthe usualspring pressed side bolts (notshown) but which side bolts also serve -chest J fixedly in the bore H.

to clamp the rotation ratchetO and thevalve'.

, The back'head T has a throttlevalvechame ber;U for a throttle..valve V whereby the admission of pressure fluid into the drill may be controlled. 7 Thethrottle valve Vias illus trated is of'the rotary type and isaccordinglyprovidedwith a lever W whereby it may bemanipulatedr Thejpressure fluid maybe 7 introduced into a central chambertX :in the munication with the pressure? fluid sup v1y.- In the wallet the throttle valveVis a p port throttle'xvalve which maybe in' constant com Yiwhich in theopen positionofthelthrottle valveregisterswith a passage Z leading to a supply reservoir 1b in the front endof the back headrT. L a The plate L is. recessed to form a :valve chamberi'c, theopposite endsd ande'xof which communicate with thersupply reser-i voirb through suppl passages f and g re spectively'. and extending throughythe. plate K7 and the rotation ratchet O: f The valve chamber c-is intended'to' accommodate aidistributing'valve h of the oscils latory platetype having a" central fulcrum y..vvhereon said valve is adapted to rock from one limiting position to the other..- surefluid distributed by .the -valve h flows into the rearward end of the; pistonchamber G through aninletpassage-lc in the plate L and into the front end of the pistonchamber through'an inlet passageo formed in the plate Land the'wall of the cylinder A.

The contiguous surfaces ofithe plates and K serve as-seating.surfaces p and g against which the'opposite sides ofthe valve ill-may seat; In the seating-surface p and g surrounding the inlet openings of the-passages lc and 0 are grooves v" ands which serve tomininnze the area ofcontact between' the seating surface 39 andthe forward surfaces The. preswhile. not causing the piston to short stroke,

7 the valve chamber. a,

of the wings t and u of the valve, and also to act as pressure chambers into which pressure fluid may be admitted to act against the for-' pressure fluid to flow over the edges of the raised portions of the wings of the valve during its course to the cylinder. While this method-has been reasonably satisfactory, it involves a degree of accuracy in tliemachin ing of the valve and a delicate balance and apportionment of areas which greatly adds to the cost of manufac turing. In certain cases it has also been found that when thus constructed the suction created byathe pres-' sure fluid fduring-the course over'the raised end of the valve tended to slightly raisethe seated end of the valve and thus admit a portion of pressure fluid into the piston chamber in advance that thisleakage of pressure fluid, coupled with the-compression,created by the piston, absorbed some of the force of the blow and,

it would however at times decrease the drilling efliciency considerably. I

Thepre'sent inventiontparticularly aims to eliminate the foregoing objectionablefeature andto th's endqthe valve h is providedinits wings t and u with ports/0' and w respective ly. There'may beone ormore of these ports depending .upon the number ofsupplypassages, three; are shown in this instance in each swing for .the purpose of illustration,

' and said port or ports are so located in the wings-that they will registerwith the. supply passages to-admit pressure-fluidfrom; the supply reservoir 6 into theforwardeend of from whencethe pressure fluid will flow through ztherinletpas- .its course through sages 10' and o'into the ends ofthe piston chamber. V.

The ports 0 land ware also 'preferably'of somewhat larger, cross sectional area than the supply passages wherewiththey are adapted a)? register'so that the pressure fluid during the valve will in. no wise exert a force thereon tending to tilt it from its limiting position. In other words only those forceswhich act in proper sequence and are dependent on the movementof the piston D .will be effective to actuate the valve. 1 The seating surfaces 17 an'dg. are'so spaced that the oppositessides of thewings t and u may lie flush thereagainst: .In :this way when the wings are raised, their rearwardsurfaces will'lie snugly against the seating surface. g sox that there will be no pressure fluid be: tween the rearward surfaces of the valve and the seating. surfaceq: I

' .Aswill be observed, the inlet openingsof.

of the piston. The result was ply passages f and g and the ports '0 and 'w register only with-the supply passages and with the grooves r and s.

l The operation of the device is as follows: With the throttle valve 2; in the open position illustrated, pressure fluid willflowtherefrom. through the passage Z into "the supply reservoir 6, thence through the supply passage g intothevalvechamber c, with the valve 1 occupying the I position illustrated, "pressure fluid will" flow through the raised wing it, thatis, through the ports 4; into the "front end of the valve chamber 0 and thence through the inlet .passage is intothe rearward end of the piston chamber C to drive the piston D forwardly. "At the same time pressure fluid will occupy the opposite end d of thevalve chamber .and will press against. the rearward surface of the :wing u to hold the valve firmly seated; Thisp-ressure'however, is augmented by that flowing from-the opposite end 6 ofthe valve chamber'and acting against theforward surface of the wing 25'. Although pressure fluid will flow through the port w into the groove sto act against a portion of theforward surfaceof the wing at, this PIGSSUIGIWl'll not be 'eflectiveto iniany way disturb the position of the valve.

As the piston D proceedsforwardly, the? free exhaust port B will be covered thereby and fromthat point on the air in-the front end of the piston willbe compressed and will-flow through the-inlet passage 0 to act against an area'of the forwardsurface 'ofthe wing u equal to the cross. sectional area of the inlet passage '0. Asft'he piston new tinues forwardly, it will overrun-the free :exhaust port B and the fluid utilized for actu ating it forwardly will then be vexhausted-to; theatmosphere. This will cause an abrupt drop inpressure beneath the wing t and'the. force of the compression in the .inlet'passa'ge 0 and the pressurefluid'in the groove sfwill then tilt the valve toits other extreme position. i In the new positionof'the valve, the inlet passage k willbe covered by the wi nglt and the port w will be inregistry with the supply passage :so that pressure fluid may 'iflow directly through these ch-armels from the supplyres'ervoir Z) i-nto thefront endofthe valve chamber and: thence through-the inlet passage-0 into the front end of the pist'Oncha'msion in the rearward end o f the" piston ch'amberiand the pressure fluid in the grooves] will a'gain'tilt the'valve h to theits' initial position. T F I j Iclaimi .7 I

In a fluid actuatedlrock drill, .the combi covers the free exhaust port B the compre'snation of a cylinder and a piston, an exhaust port for the cylinder, a valve chestcomprising a pair of plates forming a valve chamber, seating surfaces on the contiguous portions of the'plates,supply passages in one plate forconveying pressure fluid toone end of the valve chamber, inlet passages in the other plate for conveying pressure fluid from the valve chamber to the cylinder, pressure chambers in the second'said plate dissociated from the inlet passage, an oscillatory plate valve in the valve chamber having apair of wings to control the'inlet passages, said wings being adapted to seat against thefseating surfaces of both plates, and a port in each wing to register with the supply passages and through which pressure fluid flows into the valve chamber for supplying the inlet passages in one position of the valveand to register with the pressure chambers in another position of the valve for supplying pressure fluid to said pressure chambers to assist in throwing the valve. V In testimony whereof I'have signed this specification.

WILLIAM A. 1 SMITH, J1; 

